The Brave Blossoms kick-started this World Cup into life by deservedly and convincingly beating Ireland in Shizuoka.
A match that started promisingly for Joe Schmidt's men was blown off course as a fit, skilful and daring Japan side kept hold of the ball and tired out their opponents in hot and humid conditions.
Here is how we rated the Irish team.
Rob Kearney 6
A testing return to the first team as Japan ran and ran and ran at the Irish backline. Showed great strength to score the second try and defended in his usual solid fashion. Clever kick for Stockdale to chase turned a fast Japanese defensive line.
Keith Earls 6
Flashes of his jinking self at times but a loose offload at start of second half opened the field for Japan. Moved into midfield temporarily for Farrell's HIA and did not look out of place. A good contest in the air for Carbery crosskick set up an attack. Despite being peripheral to action for long periods, it was his chase and tackle at death that earned losing bonus point.
Chris Farrell 6
Tackled like a demon as he fought to push back Japanese tide. His quick hands caught eye again early on in attack but ran into Stander to concede an attacking scrum at vital time.
Garry Ringrose 7
Three exciting early breaks showed the Leinster man was in the mood. The first try was his just rewards - a massive leap to gather Carty's crosskick and finish. Channelled his inner Stephen Ferris to pick up Matsushima and carry him backwards.
Jacob Stockdale 6
Showed defensive composure to gather an awkward hop with Kotaro Matsushima lurking. Finished the game at full-back and asked a few questions of Japanese defence with his pace, off limited opportunities.
Jack Carty 6
A curate's egg of a performance. Started brilliantly and was not lacking for confidence on his first Rugby World Cup start, making Ireland's first try with an inch-perfect cross kick. Even better for second try as he tapped back his own chip for Rob Kearney. Kicked a restart dead to give Japan one more attacking platform before half-time. Spilled a catch forward and kicked too long in second half.
Conor Murray 5
Kicked a lot less in the first half than against Scotland. Great tackle on Mafi to dislodge ball and win a scrum. Tried to pick up the pace when chasing the game, which led to one forward pass. Seemed to be in referee's crosshairs, conceding three penalties, one of which was an offside with 10 minutes to go that gave Japan a seven-point lead.
Cian Healy 6
Nothing wrong with his scrummaging technique, or anything else, early on. After a week when he was at the centre of a Japanese media campaign on scrum discipline the Leinster loosehead appears to have been pinged for the one scrum penalty.
Rory Best 5
One overthrown lineout led to three points for Japan in the first half and a poor throw spoiled a great attacking platform early in second half. His trademark work at ruck minimised by the speed of Japanese attack.
Tadhg Furlong 6
His grubber kick for Keith Earls to chase another unorthodox highlight from the Wexford prop. Hesitated at ruck to allow Japan to steal early in second half and he got a bang to the face that saw him withdrawn for a HIA.
Iain Henderson 6
Great hands to gather a forceful pass from Murray early on, but most of this performance characterised by grunt. Lots of tackles, lots of ground work, but another influential Irish player to be bypassed at times by non-stop Japanese opponents.
James Ryan 7
Important early tackle - the first of an incredible 10 in the first half from the Irish workhorse. Penalised with the ball when isolated during one of Ireland's rare second half attacks but otherwise his usual excellent self.
Peter O'Mahony 6
Looked delighted to be given his second shot after concertinaed opening outing. Threw himself into everything. Lots of tackling and rucking early on. Unlucky not to steal a defensive lineout but came to attention of referee Gardner in the second half for repeatedly going off his feet and replaced by Rhys Ruddock.
Josh van der Flier 6
Rory Best was relieved to see the speeding openside on his shoulder as Japan looked like countering through a Matsushima chase. A constant pest, but penalised at ruck before half-time, which led to three points.
CJ Stander 6
Not as many opportunities to run this time out but still made most metres among pack. Put in a decent defensive shift. Superb at base of the scrum on a number of occasions to keep the setpiece moving forward.
REPLACEMENTS
Andrew Porter for Tadhg Furlong (46 minutes, HIA & 61 mins) 5
Penalty won on first put-in after his introduction. Great instinctive tackle on Nagare stalled a Japanese attack.
Dave Kilcoyne for Cian Healy (46 mins) 6
Dave Kilcoyne has landed#jpnvire #rwc2019 #rterugby https://t.co/yEY7ArlYJA pic.twitter.com/l7T7BKw9nt
— RTÉ Rugby (@RTErugby) September 28, 2019
Made two huge tackles inside a minute of his introduction. Brilliantly stopped Leitch later during a combative appearance.
Rhys Ruddock for O'Mahony (56 mins) 5
Like Kilcoyne he made an early impact on defensive side. His power was useful as Ireland chased the game with a simple approach.
Jordan Larmour for Farrell (60 mins, HIA) 4
Threw intercepted pass to bring Ireland's best second half attack to an end and give Japan the territorial advantage they needed to see the game out.
Joey Carbery for Carty (61 mins) 5
Injected a little life and unpredictability into Irish attack but could not find a gap in Japanese defence.
Sean Cronin for Best (61 mins) 5
Couple of carries but no major impact in his first appearance of World Cup.
Tadhg Beirne for Henderson (66 mins) 5
Important steal within seconds of introduction.
Luke McGrath for Kearney (69 mins) 5
Filled a gap on the wing.
